The English word “salvation” comes from the late Latin salvationem, which comes from salvare, which itself is from the Latin salvus, meaning “healthy” or “safe.” The proto-Indo-European (PIE) root of salvus is solwos, the base of which is *sol-, “whole”.
The English word “catholic” comes from the French catholique, which comes from the late Latin catholicus, which in turn is from the Greek katholikos, which itself is derived from the Greek words kata, meaning “about/concerning”, and holos, meaning “whole.” Thus, as I’m sure many of you aware, “catholic” means “universal” (i.e. “concerning the whole”). But from whence comes holos? Yup, from the same PIE root *sol- that salvation also ultimately comes from.
So even though the two English words “salvation” and “catholic” sound and look nothing alike, they are ultimately cognates!